1. Field of the Invention
The present invention relates to a mobile station using a plurality of network access identifiers (NAI) and, more particularly, to a method and system for rapid application switching that may speed up switching between data service applications having assigned network access identifiers.
2. Discussion of the Background
A user on the move may desire his mobile station to maintain a data session with a home network. In standard wired Internet Protocol (IP) networks, hosts are assumed to be fixed and have a permanent IP address for correct routing of data packets. If a mobile station moves from the home IP network to another IP network, a new IP address must be assigned by the other IP network to the mobile station. An IP address change may interrupt an ongoing data session. To solve this problem, the Internet Engineering Task Force (IETF) has proposed Mobile IP.
Mobile IP is a communication protocol that permits a mobile station to move from one network to another while maintaining a permanent IP address. Mobile IP is an effective means for working in wired and wireless environments where users need to carry their mobile stations across multiple subnets with different IP addresses. Mobile IP may also be used in roaming areas between overlapping wireless systems.
Network access identifiers (NAI) may be used along with Mobile IP to identify users requesting access to a network. A subscriber of an access provider network may use an assigned network access identifier to access the network for an IP-based service. A network access identifier includes subscriber information and domain information, and can also be used to assist in the routing of messages requesting user authentication.
An application, which delivers an IP-based service (for example, access to the Internet) to the user, is assigned an NAI. When the user activates a first application to receive a first data service from the access provider network, an NAI associated with the first application is authenticated, and then the first data service begins. Thereafter, when the user activates a second application for a second data service, an NAI associated with the second application is authenticated, and then the second data service begins.
When switching from the first application to the second application, the mobile station may deactivate protocol programs providing a communication link between the first application and the access provider network, and activate new protocol programs to create a communication link between the second application and the access provider network. In this case, repeated activation and deactivation of protocol programs for creation and release of communication links between applications and the access provider network may unnecessarily delay switching between applications.